Castle gets abducted and must solve puzzles and mind games with a group of strangers. Meanwhile, Beckett and her colleagues race against the clock to find Castle and capture a killer.
A Russian diplomat's son is killed, leading Castle and Beckett to learn about international crime and foreign politics as Castle is tasked with keeping a Russian security officer busy.
Castle takes the stand as the key witness in a murder trial, but then new info emerges late in the case, leading him and Beckett to rush to prevent a miscarriage of justice.moreless
A body is found in a theater where Martha is working, so Castle and Beckett investigate and are surprised to learn how cutthroat Acappella singers can be.